This invention relates to timepieces and more particularly relates to self-winding timepieces, particularly wristwatches, which are wound in response to change in temperature and may have infinite autonomy.
Almost all, if not all, wrist watches, other than battery powered or other electrically powered watches receive energy for winding the main spring through a main spring barrel arbor from a winding weight or rotor in the watch which rotates in either direction due to movement of the watch wearers arm and wrist. Such movement of the wearer""s arm and wrist produces acceleration of the winding weight or rotor in either direction about a pivotal axis and resultant bi-directional rotation of the shaft upon which it is mounted. The bi-directional rotation of this shaft is converted to unidirectional rotation of another shaft, which in turn winds the mainspring.
A simple and common mechanism for conversion of bi-directional rotation of one shaft in a watch to unidirectional rotation of another shaft is known as a Pellaton mechanism. A Pellaton mechanism comprises a lever, which is bifurcated at one end, and the bifurcated arms are acted upon by a rotating cam or eccentric pin to produce an eccentric oscillating motion. Spring loaded pawls on the lever engage a ratchet wheel at spaced apart locations on the ratchet wheel and unidirectionally rotate the ratchet with the rocking or oscillating motion of the lever induced by the winding weight or rotor. Examples of Pellaton mechanisms are shown in U.S. Pat. Nos. 2,696,073 and 4,174,607, as well as other references. Another mechanism for such conversion is known as a wig-wag mechanism. In this mechanism, a pinion on the bi-directionally rotatable shaft drives a linearly displaceable wig-wag gear, which will engage one of two other gears dependent on the direction of rotation of the wig-wag gear. The gear arrangement is such that the mainspring barrel will always be driven in a direction to wind the mainspring.
Self-winding wrist watches generally have an autonomy or power reserve of about one and one-half to three days. The terms xe2x80x9cautonomyxe2x80x9d and xe2x80x9cpower reservexe2x80x9d refer to the time a self winding wrist watch will continue to run if fully wound, but not worn.
Attempts to lengthen power reserve time have generally focused on the storage capacity of the mainspring. A well known watch maker, Patek Philippe, has recently announced a new limited quantity wrist watch, which will run for seven days. This watch requires two mainsprings. The mechanism of U.S. Pat. No. 5,119,348 provides room for an enlarged mainspring within and coaxial with the winding weight and is stated to store energy sufficient to keep the movement running for up to eight days. The 2000, 45th edition of International Wrist Watch magazine has reported on a wrist watch with autonomy of one thousand hours. This watch contains and extremely large mainspring and due to large power losses the time keeping is not accurate at the present time
The present invention departs from prior art designs of self winding watches and focusing on the mainspring by providing a new, but one of natures oldest, energy source which gives the watch essentially infinite autonomy, so long as the watch is not left in an environment of small tolerance temperature control.
An object of this invention is to provide a new and improved self-winding timepiece having essentially infinite autonomy.
Another object of this invention is to provide a watch having a new energy source for self-winding with an energy transmission system which provides essentially infinite autonomy.
A further object of this invention is to provide a watch having a new and improved energy source, which is responsive to change in temperature to effect self-winding.
A further object of this invention is to provide a watch with an element, which has movement in response to change in temperature and mechanisms for converting such movement to rotational movement for self winding of the watch.
Briefly stated, the invention comprises the provision of a temperature sensitive element within a watch which includes a casing, watch movement, mainspring and a bi-directional rotation to unidirectional rotation mechanism where the temperature sensitive element has angular motions with changes in temperature and such movement produces energy to wind the mainspring. More specifically, the invention in one form thereof utilizes a temperature sensitive bimetallic coil, which upon expansion and contraction rotates a driver member, which produces rotation of a shaft in the winding mechanism and effects self winding of the watch. The free or outer end of the coil will angularly deflect with change in temperature. The coil is anchored at the inner end thereof in a coil carrier or a stationary part of the watch and the outer end thereof, upon movement, will drive a driver member with an internal gear. The driver member, in one embodiment of the invention, will in turn drive a plurality of planet gears, which drive a sun gear, mounted to a shaft. The shaft of the sun gear then produces rotation of a cam or eccentric pin which drives the bi-directional to unidirectional conversion mechanism. This arrangement will provide substantially infinite self winding of the watch in a normal environment, even if the watch is not worn for a long period of time, so long as the watch is not stored or otherwise left in a closely temperature controlled environment. In another embodiment of the invention the driver member directly drives I the winding mechanism.
The invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. The invention, however, together with further objects and advantages thereof may be best appreciated by reference to the following detailed description taken in conjunction with the drawings.